About Hash Functions

A hash function takes any input and produces a fixed-length output (hash). The same input always produces the same hash, but you cannot reverse it. Hashes are used for password storage, file integrity checks, and digital signatures.

• MD5 — Fast but not cryptographically secure. Mainly used for checksums.
• SHA-1 — More secure than MD5 but deprecated for security use.
• SHA-256 / SHA-512 — Current standard, used in TLS, Bitcoin, etc.
• SHA-3 — Latest NIST standard, completely different internal design.